Field of Technology
The present disclosure relates to an organic light emitting display (OLED) device, and more particularly, to a flexible OLED device.
Discussion of the Related Art
As information technology and mobile communication technology have been developed, a display device capable of displaying a visual image has also been developed. Flat panel display devices, such as a liquid crystal display (LCD) device and an OLED device, are developed and used.
Among these flat panel display devices, since the OLED device has advantages in response time, contrast ratio, viewing angle, power consumption, and so on, the OLED device is widely developed.
An emitting diode including an organic emitting layer is susceptible to damage from moisture. To prevent moisture penetration into the emitting diode and protect the emitting diode from external impacts, an encapsulation substrate of glass is attached onto the emitting diode.
Recently, foldable, bendable or rollable display devices (hereinafter “flexible display device”) have been introduced.
In the flexible OLED device, an encapsulation film including an inorganic layer and an organic layer is used instead of the encapsulation substrate of glass. Namely, by using the encapsulation film for preventing moisture penetration into the emitting diode and to protect the emitting diode, the display device has a flexible property.
FIG. 1 is a cross-sectional view of the related art flexible OLED device.
Referring to FIG. 1, the related art flexible OLED device 1 includes a flexible substrate 10, an organic emitting diode D and an encapsulation film 20. A display area AA and a non-display area NA at a periphery of the display area AA are defined on the flexible substrate 10, and the organic emitting diode D is disposed on the flexible substrate 10. The encapsulation film 20 covers the organic emitting diode D.
The organic emitting diode D is disposed in the display area AA, and a driving part (not shown) driving the organic emitting diode D is disposed in the non-display area NA.
Although not shown, the organic emitting diode D includes first and second electrodes, which faces each other, and an organic emitting layer therebetween. In addition, a switching thin film transistor (TFT) as a switching element and a driving TFT as a driving element are formed in each pixel region on the flexible substrate 10, and the first electrode of the organic emitting diode D is connected to the driving TFT.
The encapsulation film 20 covers the organic emitting diode D and corresponds to the display area AA and the non-display area NA, in particular, overlaps both the display area AA and the non-display area NA. The damages on the organic emitting diode D in a condition of high temperature and high humidity are prevented by the encapsulation film 20.
An inorganic layer and an organic layer are alternately stacked to form the encapsulation film 20. For example, the encapsulation film 20 may have a triple-layered structure of a first inorganic layer 22 on the organic emitting diode D, an organic layer 24 on the first inorganic layer 22 and a second inorganic layer 26 on the organic layer 24.
However, when the flexible OLED device is operated under a condition of high temperature and high humidity, the emitting diode is still damaged resulting in problems in display quality and a lifetime of the flexible OLED device.